For Classic D&D if you count the module X3 Curse of Xanathon, then there are other sources which contain more (or at least more detailed) material that should be counted:
X10: Red Arrow Black Shield (for the encounters in Ethengar trying to ally them).
Gaz 10: The Orcs of Thar (for the Kugel Horde orcs).
And probably some others that I don't recall off-hand.

"If it looks like a duck and quacks like a duck, it might just be a crow".

For Classic D&D if you count the module X3 Curse of Xanathon, then there are other sources which contain more (or at least more detailed) material that should be counted:
X10: Red Arrow Black Shield (for the encounters in Ethengar trying to ally them).
Gaz 10: The Orcs of Thar (for the Kugel Horde orcs).
And probably some others that I don't recall off-hand.

Good suggestions. I was a bit hesitant to even include X3, but it is set partially in Ethengar.

The Krugel Horde are from the Hollow World. Do you mean the Yellow Orcs?